Reediting of phonograph records



y 1935- J. H. HAMMOND, JR 2,008,699

REEDITING OF PHONOGRAPH RECORDS Original Filed May 12, 1930 5Sheets-Sheet 1 INVENTOR BY .44 d

ATTORN EY July 23, 1935. J. H. HAMMOND, JR 2,008,599

REEDITING OF FHONOGRAPH RECORDS Original Filed May 12, 1930 3Sheets-Sheet 2 gwvemtoz 3 Wm? y July 23, 1935. .1. H. HAMMOND, JR2,003,699

REEDITING OF PHONOGRAPH RECORDS Original Filed May 12, 1930 3Sheets-Sheet 5 ar a? L86 g 3 I o: 114 g avwentoz 351 Aw Gwen W13Patented July 23, 1935 UNITED STATES PATENT OFFICE] a .REEDITING FPHoNoGitAPn nscoans John Hays Hammond, Jr., Gloucester,'Mass. l

Application May 12, 1930, Serial No. 451,661

Renewed October-5, 1934 a 3 Claims. (01. 179-1004 This invention relatesto the art of acoustics and more particularly to an improved methodofreediting phonograph or other records.

This invention relates more particularly to a 5 system of reediting arecordedphonograph record the'several figures or the drawings." ,7

in which the intensity of the later recording is varied at the will ofan operator.

The invention provides a method for the ,re-

editing of phonograph records in which the quality of the reeditedrecord can be varied. at will.

The invention further provides arecording system for phonograph or'other records with in-, dependent control of the upper and lowerharmonics 'so as to vary the quality of the reedited record. a

"The invention also .provides a method of reediting of phonographrecords in which the up per harmonics may'be increased at the same timethat the lower' harmonics are decreased'and vice versa.

The invention also consists of a system for the reediting of phonograph.records in which the louder tones are amplified to a greater extentthan thelweaker tones.

The invention also consists in certain new and original features ofconstruction and combinations iof parts "hereinafter set forth andclaimed.

'Al'though'the novel features which are believed to"be"characteristic orthis invention will be particul'arlypointed out in the claimsappendedhereto, the invention itself, as to its objects and advantages,.the mode of its operation and the manner of its organization may bebetter understood by referring to the following description taken in.connection with the accompanying drawings forming a part thereof, .inwhich I Fig. 1 illustrates diagrammaticallya system' of m volume'jcontrol for the re-recording 10f phono-' 4"0 graph records; a Fig. 2illustrates diagrammaticallya systemof volumeandquality control for'there-recording of phonographrecords; and

, Fig.'f3.illustrates diagrammaticallya system of 7 volume controlinwhich the amplification isautomatically varied in accordance withthesignal strength. 1 Like 'reference'charac'ters idenoteilike parts-inilnitheifollowing description and'in the claims parts'w'illbeidentified'by specific namesfor con- Nenience; but they are intended tobe i as generic in their application to similar part's' as the art,Will. .permit.

'This device is connected by two flexible iconductors H and 18 to apotentiometer resistance I9. One side of this resistance ,is connectedby conductor 2| to a battery 22, the other side ,of

which 'is connected to the filament of a space dischargedevice 23. Theother sideofsthis filament is connected to a battery 24 which inturn isconnected to the primary of a transformer 25, the other side of which isconnected to the plat e of the space'discharge device 23. The grid ofthis device is connected by a flexible conductor 26 to a contact 27which slides over the resistance I9. This contact is mounted on, butinsulated from, a shaft28, to the end of. which issecured aknob 29. g

The secondary of the transformer 25- is con} nected to an amplifyingsystemin the casingQB-l. The output of this amplifier is connected bytwo conductors 32 and 33 to a loud speaker 34. aThe conductors 32 and'33 are connected by branch conductors 35 and 36 to a double pole switch31, the other side of which is connected by two flexible conductors 38and 33 toanengraving-mechanism M which is provided with an engravingtool42. The mechanism AI is mounted on the end of an arm 43 which is pivotedto a member 44, which is mounted for rotation on a casing .45, whichcontains a driving mechanism; provided with a shaft '46 to which issecured. a plateAl. Resting on this plate is the phonograph tablet 48 onwhich is to be engraved the reedited sound record by the tool 42. Themember 44 -may b e slowly'rotated by mechanism inthe casing .45; so astocausethe tool-42 to form a spiral groove-.on the top of the tablet 48. qa In the operation of thissystem a phonograph record M is placed on theplate [3 andthemechanism in thecasing ll is-started-rotating. ELheneedle of the pick-up device is then placedin'the groove of therecordill. The music or other Se,-

lection'from this record is then amplified by "the amplifier 3landreproduced by the loudspeaker Afterthe record has been p ay d once, he:op

inal record I4 is played, the music from it will be picked up by thepick-up I6, amplified by the amplifier 3I, and sent to the engravingmechanism 4 I thus making a record of the music on the blank tablet 48.

As the part of the music is reached which should be increased inintensity, the operator rotates the knob 29 in a clockwise direction,thereby increasing the amount of current sent to the engraving tool 4I,which increases the intensity of the record at this point. If a point isreached where the record should be decreased in intensity, the knob 29is rotated in a counter-clockwise direction thereby decreasing thecurrent sent to the engraving mechanism 4I, thereby decreasing theintensity of the record made on the record disk 48.

, In this way the intensity Values of any, record may be varied at willso as to produce entirely different and more pleasing effects than thosefrom the original record, which may be either an old record or a newone.

Referring to the modified form of the invention shown in Fig. 2, thephonographic reproducing mechanism is the same as that shown in Fig. 1.In this case, however, the conductors I1 and I8 are connected to theprimary of a transformer 55, the secondary of which is connected to twofilter circuits 56 and 51 each comprising a group of condensers andinductances as shown. The filter circuit 56, which is a high passfilter, allows high frequency currents to pass, such as those of theupper half of the voice and music range, and the filter circuit 51,which is a low pass filter, allows low frequency currents of the lowerhalf of this range to pass. The filter circuits 56 and 51 are connectedto two space discharge tubes 58 and 59, the outputs of which areconnected to two transformers BI and 62.

The secondaries of these transformers 6| and 62 are connected to twopotentiometers 63 and 64, the movable contacts of which are moved bymeans of a handle 65. The potentiometers ,63 and 64 are connected to twofilter circuits 66 and 61, the condensers of which are variable and arecontrolled from a handle 69. These condensers are so connected to thishandle that, as the capacity of one set is increased, the capacity ofthe other set is decreased. The filter circuits 56 and 51 are connectedthrough tubes H and 12 to a transformer 13. The secondary of thistransformer is connected to a push pull amplifier 14, the output ofwhich is delivered from transformer 15.

The secondary of this transformer 15 is con nected to the conductors 32and 33 which go to the loud speaker 34. The conductors 32 and 33 areconnected by the branch conductors 35 and 36 to a double pole switch 31,the other side of which is connected by two flexible conductors 38 and39 to the engraving mechanism M.

The operation of this system is similar to that shown in Fig. 1, theintensity of the re-recording being controlled by the handle 65. Bymoving this handle in a counter-clockwise direction the intensity isincreased due to the increased energy which is picked up by thepotentiometers 63 and 64, and by moving the handle in a clockwisedirection the intensity is decreased.

The energy from the pick-up device I6 passes through the transformer 55to the filter circuits 56 and 51, the former allowing the higherfrequencies' to pass and the latter thelower frequencies.' Thesecurrents are then amplified by the space discharge tubes 58 and 59 fromwhich they Pass through the transformers 6| and 62 to the potentiometers63 and 64. Here any desired proportion of the energy from the lower andupper sound ranges may be picked up depending upon the setting of thehandle 65.

The energy from the potentiometers 63 and 64 then passes through thefilters 66 and 61. These are normally in such a position that thefrequen cies passing through these filters are unaltered and, therefore,the relative intensities of the treble and bass harmonics are the sameas those in the original music. If,-however, the handle 68 is shifted inone direction, it will increase the capacities in the circuit 66 anddecrease the capacities in the circuit 61. This will cause less of theharmonics to be passed in the circuit 66 and more of the harmonics to bepassed in the circuit 61. In this way the brilliance of the bass notesis increased and that of the treble notes decreased. If the handle 68 ismoved in the opposite direction, the capacities in the circuit 66 willbe decreased and those in, the circuit 61 increased,

thereby making the treble harmonics richer and cutting down onthebassharmonics. l

The energy from the circuits 66 and 61 isthen amplified by the spacedischarge means H, and 12 from which it is fed to the push-pullamplifier 14 where it is still more amplified and fed to-the loudspeaker 18 and engraving mechanism 4I thus making a record of the musicon the blank tablet 48 in a manner similar to that described inconnection with Fig. l.

Referring to the modified form of the invention shown in Fig. 3, thephonograph mechanism is the same as that shown in Fig. 1. In this case,however, the conductors I1 and I8 are connected to the primary of atransformer 8|, the secondary of which is connected to a potentiometer82, the movable contact of which is operated bya handle 83. The inputcurrent is taken from this potentiometer and applied to the inputcircuit of a space discharge tube 84.

Theinput circuit of a control space discharge tube is connected inparallel'with the input circuit of the space discharge tube 84, throughcondenser 86 and the common grid return 81. This lead 81 is connected tothe movable con-tact of a potentiometer 9| which is across the commonfilament battery 92. This potentiometer 9| is operated by a handle 93. Ahigh resistance 9.4.may be connectedbetween the grid of the spacedischarge tube 85 and the grid-return 81, to provide the necessaryleakage path. A resistance is lo cated in the grid return of the spacedischarge tube 84 and is shunted by a condenser 96. In series with theresistance 95 in the grid return 81 are batteries 91 and 98. v

The output circuit of the control space discharge tube 85 includes theprimary of a transformer IIII and a source of power I 82. The sec.-ondary of this transformer is connected in series with a rectifyingdevice I 93 and a battery I04 all across the resistance 95. Therectifying device I03 may be of any suitable type, as for example, athree electrode spacedischarge tube havinga filament which maybeenergized by a battery I05. The output circuit of the main spacedischarge tube 84 comprises a transformer I06 which is shunted by a highresistance IIITin order to ob tain the proper fidelity curve. Thesecondary of this transformer is connected to 'a potentiometer I I I,the movable contact of which is controlled by a handle II2.Thispotentiometer is connected through a transformer I I3 to the inputcircuit of a push-pull amplifier I I4. The output. circuit of thisamplifier is connected through a transformer recording being controlledby the handle I I5 to the conductors 32 and 33 which go to the loudspeaker 34. The conductors 32 and 33are connected by branch conductors35 and 36 to a double pole switch 37, the other side of which isconnected by two flexible conductors 38 and 39 to the engravingmechanism ll.

The general operation of this system is similar tothat shown in Fig. l,the intensity of the H2 which controls the amount of energy fed to thepush pull amplifier H4 and, therefore, to the loud speaker 34 andengraving mechanism at. The handles 33 and 93 control the dynamic rangeand quality, the former controlling the amount of energy fed to thedynamic multiplier, so that it will operate in its proper range and notcause an overloading of the space discharge tube 84 and the lattercontrolling the initial setting for the space discharge tubes 84 and 85,thus determining the dynamic range.

The amplifying characteristics of the space discharge tube 8d aredetermined by its grid potential. This in turn is determined by thebatteries 91 and 98, the voltage drop in the resistance 95 and thesetting of the potentiometers 82 and 9!. The voltagedrop of theresistance 95 is governed by the amplitude of the impressed signals,which are applied to control the tube 85 and determine the space currentin that tube, which is passed through the primary of the transformerIiil. The current in the secondary of this transformer is appliedthrough the rectifier H33 to the resistance 95. An unidirectionalcurrent is thereby produced in this resistance which is proportional invalue to the average amplitude of the impressed signal, thus controllingthe amplification characteristics of the space discharge means 86.

It is thus seen that in the form of the invention shown in Fig. 3, theintensity of recording may be controlled by one handle while the qualityand dynamic range may be controlled by the other two handles. This formalso has the advantage of the dynamic multiplication in which theamplification ratio is varied in accordance with the strength of theimpressed signal, being greater for strong signals than for weak ones.

Another advantage of the system disclosed in Fig. 3 is that it can beused for re-recording records without the manual operation of handles83, 93 and H2. In this case the inherent performance of the circuit willcause the louder notes to be amplified to a greater extent than the 1.In a reediting system, a primary tablet having a record of a soundselection thereon, a secondary tablet for recording the reeditedselection, a pick-up device cooperating with said primary tablet, arecording device cooperating with said secondary tablet, a path betweensaid devices, said path including an amplifier tube, variable means forcontrolling the energy fed to said tube, variable means for controllingthe energy delivered by said tube, variable means for controlling thedynamic range of the tube, and. means for causing said tube to amplifythe weaker tones less than the stronger tones.

2. In a re-editing system, a primary record member having a record of asound selection thereon, a secondary record member for recording there-edited selection, a pick-up device 00- operating with said primaryrecord member, a recording device cooperating with said secondary recordmember, a path including an amplifier between said devices, and meanscontrolled by the change in average intensity of the sound energyproduced by said primary record member for controlling the amplifier toimpress the selection with modified dynamics on said secondary recordmember.

3. In a re-editing system, a primary record member having a record of asound selection thereon, a secondary record member for recording there-edited selection, a pick-up device cooperating with said primaryrecord member, a recording device cooperating with said secondarymember, a path including a modifier between said devices and meanscontrolled by the average nature of the sound energy produced by saidprimary record member to control the modifier to impress the selectionin its modified form on said secondary record member, whereby soundreproduced from said secondary record has different characteristics fromsound reproduced from said primary record.

JOHN HAYS HAMMOND, JR.

